The present invention relates to the switching of signals, and more particularly to a switcher that uses shared processors, such as compression decoders, color correctors or the like.
It is projected that, particularly in an HDTV (High Definition TeleVision) plant, most of the disk and storage devices in a television plant will use compression. It is desirable to interconnect these devices in their native compressed formats. One problem with this approach is that production switchers, master control switchers and digital effects systems, all of which operate in a non-compressed format, require de-compression functions on their inputs. For a large switcher with a great number of inputs this could result in a significant economic burden due to the large number of de-compression functions required, i.e., one for each input. Other functions also are desired in a switcher, such as color correctors. But again having a color corrector for each input is expensive in cost and hardware.
Although a switcher has a large number of inputs, only a small number of them are actually active at the output of the switcher. For the majority of the time there may actually only be one input routed to the output of the switcher. The switcher typically includes a tally function that indicates all of the inputs which are actively used to generate a program output at any particular time. Typically where two videos are combined, one a foreground video and another a background video like a weather man in front of a weather map, and characters are overlaid on top, three input sources are being used to create the program output, and the tally function causes switcher lights to illuminate, indicating the three inputs being used.
What is desired is a switcher with multiple inputs that minimizes the number of processing functions required at the input to produce a program output.